Organopolysiloxane composition, and organic silicon compound and production method therefor

ABSTRACT

This organopolysiloxane composition, when cured at room temperature by moisture in the atmosphere, provides a silicone rubber cured product having good self-adhesiveness to a magnesium alloy. The organopolysiloxane composition contains (A) an organopolysiloxane having a hydroxy group and/or a hydrolysable silyl group at both ends of the molecular chain, (B) an organic silicon compound other than (A) and (C), having at least three hydrolysable groups bonded to a silicon atom per molecule, and/or a partial hydrolysis-condensation product thereof, and (C) a silane coupling agent having a specific molecular structure having a carboxylic acid silyl ester bond. Furthermore, a novel compound, having an alkoxysilyl group and a carboxylic acid silyl ester group per molecule, can have improved adhesiveness/bonding properties with respect to a base material due to the effect of carboxylic acid after hydrolysis thereof.

TECHNICAL FIELD

The present invention relates to an organopolysiloxane composition thatprovides a silicone rubber cured product exhibiting excellent magnesiumalloy adhesion by being cured at room temperature.

The present invention also relates to a novel organic silicon compound,hi particular, the present invention relates to a novel carboxylic acidsilyl ester group-containing organic silicon compound useful as a silanecoupling agent, a silylating agent, an adhesion aid, and the like, and aproduction method therefor.

BACKGROUND ART

A silicone rubber obtained by curing a room temperature-curableorganopolysiloxane composition (so-called silicone rubber composition)is excellent in safety, and durability and adhesive properties as arubber, and therefore is widely used in a building-related field, atransport-related field, an electric/electronic part-related field, andthe like.

An application of a cured product of a room temperature-curableorganopolysiloxane composition (silicone rubber cured product) oftenrequires high adhesive properties. By adding, as a tackifier, ahydrolyzable organosilane compound having a functional group-containingmonovalent hydrocarbon group such as an amino group, an epoxy group, amethacryl group, or a mercapto group (a carbon functional silane or asilane coupling agent) to the room temperature-curableorganopolysiloxane composition, stickiness and adhesion to a substratehave been improved.

Conventionally, as an amino group-containing alkoxysilane compound,γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane,γ-aminopropyl methyldimethoxysilane, γ-aminopropyl methyldiethoxysilane,N-β-aminoethyl-γ-aminopropyl methyldimethoxysilane,N-benzyl-γ-aminopropyl trimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, β-aminoethylaminomethyl phenethyl trimethoxysilane,N-[m-aminomethylphenylmethyl]-γ-aminopropyl trimethoxysilane, and thelike are known (Patent Document 1: JP-A 2008-163143), and as an epoxygroup-containing alkoxysilane compound, 2-(3,4-epoxy cyclohexyl))ethyltrimethoxysilane, 3-glycidoxypropyl trimethoxysilane,3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and the like are known (Patent Document 2: JP-A2004-307723). As a methacryl group-containing alkoxysilane compound,3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyl methyldimethoxysilane,3-methacryloxypropyl methyldiethoxysilane, and the like are known(Patent Document 3: JP-A 2006-156964), and as a mercaptogroup-containing alkoxysilane compound, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyl methyldimethoxysilane, and the likeare known (Patent Document 4: JP-A H09-12861). As described above, alarge number of alkoxysilane compounds have already been used asadhesion aids, but a demand for improving stickiness/adhesion to asubstrate has been increasing year by year.

Meanwhile, in recent years, a magnesium alloy represented by AZ-91D hasbeen often used for an information electronic device such as a mobilephone, a digital video, a digital camera, a liquid crystal projector, aplasma display, a personal computer, an MD player, or a DVD recorder,and a transport device member such as an electrical component, anautomotive oil pan, an intake manifold, a lock housing component, asteering upper bracket, or a steering wheel due to characteristics oflight weight, high strength, corrosion resistance, designability, andrecyclability. An organopolysiloxane composition for adhering to amagnesium alloy, having good self-adhesion to these members is required.

However, the magnesium alloy is an adherend having very pooradhesiveness, and therefore a chemical conversion treatment isindispensable for adhering to the magnesium alloy. Studies of a sealantand an adhesive agent exhibiting good self-adhesion without thetreatment have not been often performed so far. That is, only thefollowing several methods have been proposed so far for anorganopolysiloxane composition having self-adhesion to a magnesiumalloy. JP-A 2003-535152 (Patent Document 5) proposes a compositioncomprising a curable silicone, a filler and an amino group-containingsilane adhesion promoter. JP 3818365 (Patent Document 6) proposes acomposition using a silicone oil and an inorganic compound containing ametal element having a smaller ionization tendency than magnesium as acuring agent. JP 4553110 (Patent Document 7) achieves adhesion to amagnesium alloy by using an acidic silane coupling agent in which a 5%silane coupling agent aqueous solution has a pH of 7 or less.Furthermore, JP-A 2007-204575 (Patent Document 8) reports adhesion to amagnesium alloy by using a base oil, an organopolysiloxane having aterminal silethylene bond, and a zinc compound as a filler. However, inPatent Document 5, effectiveness of the amino group-containing silaneadhesion promoter such as γ-aminopropyl trialkoxysilane ortrialkoxypropyl ethylenediamine is insufficient. In Patent Documents 6and 8, there is a restriction by a filler and a base oil used, andtherefore Patent Documents 6 and 8 lack flexibility in material design.Patent Document 7 has a drawback that use of the acidic silane couplingagent exemplified results in a decrease in adhesion to a magnesium alloyafter a chemical resistance test.

PRIOR ART DOCUMENTS Patent Documents

Patent Document 1: JP-A 2008-163143

Patent Document 2: JP-A 2004-307723

Patent Document 3: JP-A 2006-156964

Patent Document 4: JP-A H09-12861

Patent Document 5: JP-A 2003-535152

Patent Document 6: JP 3818365

Patent Document 7: JP 4553110

Patent Document 8: JP-A 2007-204575

SUMMARY OF INVENTION Technical Problem

An object of the invention, which has been made under theabove-mentioned circumstances, is to provide an organopolysiloxanecomposition that cures at room temperature by moisture in the atmosphere(crosslinking by a condensation reaction) to provide a silicone rubbercured product having good self-adhesion to a magnesium alloy,particularly to provide an organopolysiloxane composition for adheringto a magnesium alloy.

Another object of the present invention is to provide a novel organicsilicon compound useful for a silane coupling agent, a silylating agent,an adhesion aid, and the like for improving stickiness/adhesion to asubstrate, and a production method therefor.

Solution to Problem

The present inventors made intensive studies in order to achieve theabove object. As a result, the present inventors have found that byusing a compound having both an alkoxysilyl group and a carboxylic acidsilyl ester group represented by the following general formula (3) inone molecule, stickiness/adhesion to a substrate can be improved due toan effect of a carboxylic acid after its hydrolysis reaction.

Furthermore, the present inventors made intensive studies focusing onspecificity of a magnesium alloy adherend. As a result, the presentinventors have found that an organopolysiloxane composition comprising(A) an organopolysiloxane represented by the following general formula(1) and/or (2), (B) an organic silicon compound other than components(A) and (C), having at least three silicon-bonded hydrolyzable groups inone molecule, and/or a partial hydrolytic condensate thereof, (C) asilane coupling agent having a specific molecular structure having acarboxylic acid silyl ester bond, represented by the following generalformula (3), and preferably (D) at least one filler provides a siliconerubber cured product having good self-adhesion to a magnesium alloy bybeing cured at room temperature (23° C.±10° C.) by moisture in theatmosphere (crosslinking by a condensation reaction).

That is, for a general adherend represented by glass, an aminogroup-containing silane adhesion promoter is effective. However, for amagnesium alloy, as is clear from the following results of ComparativeExamples using 3-aminopropyl trimethoxysilane, the aminogroup-containing silane adhesion promoter has poor adhesive properties.The present inventors have found that use of a silane coupling agenthaving a specific molecular structure having a carboxylic acid silylester bond dramatically improves adhesion to a magnesium alloy, and thatexcellent chemical resistance is achieved as compared with prior art,thus completing the present invention.

That is, the present invention provides an organopolysiloxanecomposition, an organic silicon compound and a production methodtherefor, as defined below.

[1]

An organopolysiloxane composition comprising:

-   -   (A) 100 parts by weight of an organopolysiloxane having the        general formula (1) and/or (2),        HO(SiR₂O)_(n)H  (1):        wherein R is independently an unsubstituted or        halogen-substituted C₁-C₁₀ monovalent hydrocarbon group and n is        an integer of at least 10,

wherein R and n are as defined above, Y is oxygen atom or a C₂-C₅alkylene group and m is independently 0 or 1;

(B) 0.1 to 50 parts by weight of an organic silicon compound other thancomponents (A) and (C), having at least three silicon-bondedhydrolyzable groups in one molecule, and/or a partial hydrolyticcondensate thereof; and

(C) 0.1 to 15 parts by weight of a silane coupling agent having thegeneral formula (3):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b is an integer of 0 to 3.[2]

The organopolysiloxane composition according to [1], wherein component(B) is a hydrolyzable organosilane compound having the general formula(4) and/or a partial hydrolytic condensate thereof:R⁴ _(c)SiR⁵ _(4-c)  (4)wherein R⁴ is a monovalent hydrocarbon group, R⁵ is a hydrolyzable groupand c is 0 or 1.[3]

The organopolysiloxane composition according to [1] or [2], furthercomprising at least one filler as component (D) in an amount of 1 to 500parts by weight per 100 parts by weight of component (A).

[4]

The organopolysiloxane composition according to any one of [1] to [3],which is used for adhering to a magnesium alloy.

[5]

An organic silicon compound having the general formula (3a):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b is an integer of 0 to 3, with the proviso that k is an integer of6 to 14 in a case where R³ is an aliphatic saturated monovalenthydrocarbon group and b=3.[6]

A method for producing an organic silicon compound having the generalformula (3a):

wherein R¹, R² and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, a is an integer of 0 to 2, b is an integer of 0 to 3and k is an integer of 3 to 14, with the proviso that k is an integer of6 to 14 in a case where R³ is an aliphatic saturated monovalenthydrocarbon group and b=3,

the method comprising a step of causing a reaction between

a carboxylic acid silyl ester compound having an aliphatic unsaturatedgroup at a terminal, represented by the general formula (5):

wherein R³, b and k are as defined above, with the proviso that k is aninteger of 6 to 14 in a case where R³ is an aliphatic saturatedmonovalent hydrocarbon group and b=3, and an alkoxysilane having thegeneral formula (8):

wherein R¹, R² and a are as defined above.[7]

The method for producing an organic silicon compound according to [6],wherein the carboxylic acid silyl ester compound having an aliphaticunsaturated group at a terminal, represented by the general formula (5)is obtained by a reaction between

a carboxylic acid having an aliphatic unsaturated group at a terminal,represented by the general formula (6):

wherein k is as defined above, and a halosilane having the generalformula (7):[Chem. 8]X_(4-b)—Si—R  (7)wherein R³ and b are as defined above, and X is a halogen atom.

Advantageous Effects of Invention

The organopolysiloxane composition of the present invention provides asilicone rubber cured product exhibiting excellent magnesium alloyadhesion by being cured at room temperature, and is particularly usefulas an organopolysiloxane composition for adhering to a magnesium alloy.

In addition, the novel organic silicon compound of the present inventionhas an alkoxysilyl group and a carboxylic acid silyl ester group in onemolecule, and regenerates a highly active carboxyl group by hydrolysis.Therefore, the room temperature-curable organopolysiloxane compositionincluding the organic silicon compound exhibits high stickiness/adhesiveproperties to a substrate.

DESCRIPTION OF EMBODIMENTS

The organopolysiloxane composition of the present invention contains thefollowing components (A) to (C).

(A) an organopolysiloxane having the general formula (1) and/or (2):HO(SiR₂O)_(n)H  (1)wherein R is independently an unsubstituted or halogen-substitutedC₁-C₁₀ monovalent hydrocarbon group and n is an integer of at least 10,

wherein R and n are as defined above, Y is oxygen atom or a C₂-C₅alkylene group and m is independently 0 or 1;

(B) an organic silicon compound other than components (A) and (C),having at least three silicon-bonded hydrolyzable groups in onemolecule, and/or a partial hydrolytic condensate thereof; and

(C) a silane coupling agent having the general formula (3):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b is an integer of 0 to 3.[Component (A)]

Component (A) used in the organopolysiloxane composition of the presentinvention is an organopolysiloxane to act as a main component (basepolymer) of the composition, and is represented by the following generalformula (1) and/or (2).HO(SiR₂O)_(n)H  (1)wherein R is independently an unsubstituted or halogen-substitutedC₁-C₁₀ monovalent hydrocarbon group and n is an integer of at least 10,

wherein R is independently an unsubstituted or halogen-substitutedC₁-C₁₀ monovalent hydrocarbon group, n is an integer of at least 10, Yis oxygen atom or a C₂-C₅ alkylene group and m is independently 0 or 1.

In general formulas (1) and (2), R is an unsubstituted orhalogen-substituted monovalent hydrocarbon group having 1 to 10 carbonatoms, and examples thereof include: alkyl groups such as methyl, ethyl,and propyl; cycloalkyl groups such as cyclohexyl; alkenyl groups such asvinyl and allyl; aryl groups such as phenyl and tolyl; and groups inwhich hydrogen atoms bonded to carbon atoms of these groups arepartially replaced with halogen atoms, such as a 3,3,3-trifluoropropylgroup. Among these groups, methyl, vinyl, phenyl, and3,3,3-trifluoropropyl are preferable, and methyl is particularlypreferable. A plurality of Rs in general formulas (1) and (2) may be thesame group or different groups.

n is an integer of 10 or more, particularly an integer such that theviscosity of the diorganopolysiloxane at 25° C. is within a range of 25to 500,000 mPas, preferably within a range of 500 to 100,000 mPa·s. Notethat in the present invention, the viscosity is a value measured with arotational viscometer (for example, a BL type, a BH type, a BS type, acone plate type, or a rheometer) at 25° C. Specifically, a value of nthat provides such a viscosity only needs to be an integer of usuallyabout 10 to 2,000, preferably about 20 to 1,500, more preferably about50 to 1,000.

In general formula (2), Y is an oxygen atom or an alkylene group having2 to 5 carbon atoms, and examples of the alkylene group having 2 to 5carbon atoms include ethylene, propylene, and butylene. Among thesegroups, Y preferably is an oxygen atom or ethylene.

ms each independently represent 0 or 1.

[Component (B)]

Component (B) used in the organopolysiloxane composition of the presentinvention acts as a crosslinking agent (curing agent), and is ahydrolyzable organic silicon compound other than components (A) and (C),having at least three hydrolyzable groups each bonded to a silicon atomin one molecule, and/or a partial hydrolytic condensate thereof. Theorganic silicon compound is preferably a hydrolyzable organosilanecompound represented by the following general formula (4) and/or apartial hydrolytic condensate thereof (that is, an organosiloxaneoligomer having at least two, preferably at least three residualhydrolyzable groups in a molecule generated by partially hydrolyzing andcondensing the organosilane compound).R⁴ _(c)SiR⁵ _(4-c)  (4)wherein R⁴ is a monovalent hydrocarbon group, and R⁵ is a hydrolyzablegroup, c is 0 or 1, preferably 1.

In general formula (4), examples of the hydrolyzable group R⁵ include aketoxime group, an alkoxy group, an acyloxy group, and an alkenyloxygroup. Specific examples thereof include: C₃-C₈ ketoxime groups such asdimethyl ketoxime, methyl ethyl ketoxime and methyl isobutyl ketoxime;C₁-C₄, particularly C₁ or C₂ alkoxy groups such as methoxy, ethoxy,propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy;C₂-C₄ acyloxy groups such as acetoxy and propionoxy, and C₂-C₄alkenyloxy groups such as vinyloxy, allyloxy, propenoxy andisopropenoxy.

The remaining group R⁴ bonded to a silicon atom other than hydrolyzablegroups is not particularly limited as long as being a monovalenthydrocarbon group. Specific examples of the R⁴ include a C₁-C₁₀monovalent hydrocarbon group, for example, alkyl groups such as methyl,ethyl, propyl and butyl; alkenyl groups such as vinyl; and aryl groupssuch as phenyl. Among these groups, methyl, ethyl, vinyl and phenyl arepreferable.

Specific examples of component (B) include: ketoxime silanes such astetrakis(methylethylketoxime) silane, methyltris(dimethylketoxime)silane, methyltris(methylethylketoxime) silane,ethyltris(methylethylketoxime) silane,methyltris(methylisobutylketoxime) silane andvinyltris(methylethylketoxime) silane (also known as vinyltributanoximesilane); alkoxysilanes such as methyltrimethoxysilane,vinyltrimethoxysilane, phenyltrimethoxysilane, tetramethoxysilane,vinyltriethoxysilane and tetraethoxysilane; acetoxysilanes such asmethyltriacetoxysilane and vinyltriacetoxysilane; isopropenoxysilanessuch as methyltriisopropenoxysilane, vinylisopropenoxysilane andphenyltriisopropenoxysilane; and partial hydrolytic condensates thereof.These compounds may be used singly or in combination of two or moretypes thereof.

The amount of component (B) blended is 0.1 to 50 parts by weight, andpreferably to 30 parts by weight per 100 parts by weight of component(A). If the amount is less than 0.1 parts by weight, sufficientcrosslinking cannot be obtained, thereby failing to obtain a compositionhaving desired rubber elasticity. If the amount exceeds 50 parts byweight, the obtained cured product tends to have low mechanicalproperties.

Note that component (B) represented by formula (4) is clearlydifferentiated from component (A) in having no repeating structure of adifunctional diorganosiloxane unit represented by (SiR₂O)_(n) in amolecule thereof. In addition, component (B) is also clearlydifferentiated from the silane coupling agent of component (C) describedlater in being free of a carboxylic acid silyl ester bond in a moleculethereof.

[Component (C)]

Component (C) used in the organopolysiloxane composition of the presentinvention is a silane coupling agent, having 1 to 4 carboxylic acidsilyl ester bonds in a molecule thereof, and is an essential componentfor imparting good magnesium alloy adhesive properties to a curedproduct (silicone rubber) obtained by curing the composition of thepresent invention at room temperature. As described in Patent Document7, an acid-based silane coupling agent is effective for improvingadhesion to a magnesium alloy. The silane coupling agent having acarboxylic acid silyl ester group used in the present invention has acarboxyl group protected with a silyl group while being uncured.However, the silane coupling agent regenerates a carboxyl group byremoval of the silyl group due to hydrolysis while being cured, andthereby improves an adhesive strength to a magnesium alloy. In addition,by protecting a highly active carboxyl group with a silyl group, storagestability and chemical resistance are also improved.

The carboxylic acid silyl ester group-containing silane coupling agentaccording to the present invention has a structure represented by thegeneral formula (3):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b is an integer of 0 to 3.

Here, in general formula (3), the C₁-C₁₀ monovalent hydrocarbon groupsrepresented by R¹, R² or R³ are preferably C₁-C₇ monovalent hydrocarbongroups. Among these groups, examples of R¹ constituting a hydrolyzablegroup as R¹O— include: saturated or unsaturated aliphatic hydrocarbongroups such as alkyl groups including methyl, ethyl, propyl andisopropyl, cycloalkyl groups including cyclohexy, and alkenyl groupsincluding vinyl and allyl; and aromatic hydrocarbon groups such as arylgroups including phenyl and tolyl, and aralkyl groups including benzyland phenyl ethyl. Among these groups, groups having 1 to 7 carbon atomsare preferable. For example, alkyl groups such as methyl, ethyl, propyland isopropyl are preferable, and methyl and ethyl are particularlypreferable.

Examples of R² include: saturated or unsaturated aliphatic hydrocarbongroups such as alkyl groups including methyl, ethyl, propyl andisopropyl, cycloalkyl groups including cyclohexyl group, and alkenylgroups including vinyl and allyl; and aromatic hydrocarbon groups suchas aryl groups including phenyl and tolyl, and aralkyl groups includingbenzyl and phenyl ethyl. Among these groups, groups having 1 to 7 carbonatoms are preferable. For example, alkyl groups such as methyl, ethyl,propyl and isopropyl, alkenyl groups such as vinyl, and aryl groups suchas phenyl are preferable, and methyl, ethyl and phenyl are particularlypreferable.

R³ is derived from a silyl group protecting a carboxyl group and is anunsubstituted or substituted C₁-C₁₀ monovalent hydrocarbon group.Examples of R³ include: saturated or unsaturated aliphatic hydrocarbongroups such as alkyl groups including methyl, ethyl, propyl andisopropyl, cycloalkyl groups including cyclohexyl, and alkenyl groupsincluding vinyl and allyl; and aromatic hydrocarbon groups such as arylgroups including phenyl and tolyl, and aralkyl groups including benzyland phenyl ethyl. Among these groups, groups having 1 to 7 carbon atomsare preferable. For example, alkyl groups such as methyl, ethyl andpropyl, alkenyl groups such as vinyl, and aryl groups such as a phenylare preferable, and methyl, ethyl, vinyl and phenyl are particularlypreferable.

In general formula (3), k represents the repeating number of a saturatedhydrocarbon group of a spacer connecting the hydrolyzable alkoxysilylgroup and the carboxylic acid silyl ester group in the silane couplingagent. The repeating number k of a methylene group in the alkylene grouprepresented by —(CH₂)_(k)— which is a spacer is preferably an integer of3 to 14, more preferably an integer of 5 to 13, still more preferably aninteger of 6 to 11, particularly preferably an integer of 8 to 11, andmost preferably an integer of 8 to 10. If the number of spacers is lessthan 3, synthesis is difficult. If the number of spacers is more than14, the molecular weight is too large, and adhesive properties may bereduced.

In the formula, the value of a is an integer of 0 to 2, and preferably0.

In the formula, the value of b is an integer of 0 to 3, preferably aninteger of 1 to 3, more preferably 2 or 3. In a case where the value ofb is 2 or 3, the structures of R³s may be the same or different.

Note that in the present invention, in a case where b=3 and R³ is analiphatic saturated monovalent hydrocarbon group such as alkyl group,the repeating number k of a methylene group in the alkylene grouprepresented by —(CH₂)_(k)— which is a spacer is an integer of 6 to 14,preferably an integer of 6 to 11, and more preferably an integer of 8 to10.

Specific examples of general formula (3) include compounds having thefollowing structures, but are not limited thereto.

The organic silicon compound of the present invention useful as a silanecoupling agent having a carboxylic acid silyl ester group or the likecan be produced by, for example, first, preparing a carboxylic acidsilyl ester compound having an aliphatic unsaturated group(ethylenically unsaturated group or alkenyl group) at a terminal havingthe general formula (5), by a dehydrohalogenation reaction of acarboxylic acid having an aliphatic unsaturated group (ethylenicallyunsaturated group or alkenyl group) at a terminal with a halosilane, andthen causing a reaction of the carboxylic acid silyl ester compound withan alkoxysilane having a SiH group (hydrosilyl group) in the presence ofa catalyst:

wherein R³, b and k are as defined above.

In formula (5), in a case where b=3 and R³ represents an aliphaticsaturated monovalent hydrocarbon group such as an alkyl group, k is aninteger of 6 to 14, preferably an integer of 6 to 11, more preferably aninteger of 8 to 10.

The carboxylic acid silyl ester compound having an aliphatic unsaturatedgroup (ethylenically unsaturated group or alkenyl group) at a terminal,represented by general formula (5) can be produced by the followingmethod. The carboxylic acid silyl ester compound can be produced bycausing a reaction between a carboxylic acid having an aliphaticunsaturated group (ethylenically unsaturated group or alkenyl group) ata terminal having the general formula (6): and

wherein k is as defined above,a halosilane having the general formula (7):[Chem. 33]X_(4-b)—Si—R³ _(b)  (7)wherein R³ and b are as defined above, and X is a halogen atom,in the presence of a hydrogen halide scavenger, for example, at 0° C. to150° C., preferably at 0° C. to 60° C. for about 30 minutes to 10 hours.

In formula (7), examples of the halogen atom for X include Fluoro,Chloro, Bromo and Iodo, and Chloro is preferable because of easyavailability.

A reaction ratio between the carboxylic acid having an aliphaticunsaturated group (ethylenically unsaturated group or alkenyl group) ata terminal represented by formula (6) and the halosilane represented byformula (7) is desirably set such that the molar ratio of a halogen atomin the halosilane to a carboxyl group in the carboxylic acid having analiphatic unsaturated group (ethylenically unsaturated group or alkenylgroup) at a terminal (halogen atom/carboxyl group) is preferably 1 to 2and more preferably 1.0 to 1.4.

Examples of the hydrogen halide scavenger include tertiary aminecompounds such as trimethylamine, triethylamine, tributylamine andpyridine.

The amount of the hydrogen halide scavenger used is preferably toprovide 0.8 mol to 3 mol, and particularly preferably 1 mol to 2 mol pera mol of halogen atoms in the halosilane represented by formula (7).

By causing a reaction between the carboxylic acid silyl ester compoundhaving an aliphatic unsaturated group (ethylenically unsaturated groupor alkenyl group) at a terminal represented by general formula (5) thusobtained, and an alkoxysilane having a SiH group (hydrosilyl group) inthe presence of a catalyst, the organic silicon compound of the presentinvention can be produced.

That is, the organic silicon compound of the present invention can beobtained by causing a reaction between an alkoxysilyl compound havingthe general formula (8), i.e., hydrosilyl group-containing (organo)alkoxysilane:

wherein R¹, R², and a are as defined above, and

a carboxylic acid silyl ester compound having an aliphatic unsaturatedgroup (ethylenically unsaturated group or alkenyl group) at a terminalrepresented by the general formula (5):

wherein R³, b, and k are as defined above,

in the presence of a platinum group metal catalyst, for example, at 40°C. to 200° C., preferably at 60° C. to 120° C. for about 30 minutes to15 hours.

In this case, a reaction ratio between the alkoxysilyl compound havingformula (8), i.e., hydrosilyl group-containing (organo) alkoxysilane andthe carboxylic acid silyl ester compound having an aliphatic unsaturatedgroup (ethylenically unsaturated group or alkenyl group) at a terminalrepresented by formula (5) is desirably set such that the molar ratio ofa SiH group of the alkoxysilyl compound to a terminal aliphaticunsaturated group of the carboxylic acid silyl ester compound having analiphatic unsaturated group at a terminal (SiH group/terminal aliphaticunsaturated group) is preferably 0.5 to 2, more preferably 1 to 2, andstill more preferably 1.0 to 1.5.

Examples of the platinum group metal catalyst used herein includechloroplatinic acid, an alcohol solution of chloroplatinic acid, areaction product of chloroplatinic acid and an alcohol, a platinumolefin compound complex, a platinum vinyl group-containing siloxanecomplex and platinum-carrying carbon.

The amount of the platinum group metal catalyst used only needs to be aso-called catalytic amount, and is preferably to provide 0.1 to 1,000ppm, and particularly preferably 0.3 to 100 ppm in terms of the weightof the platinum group metal with respect to the total weight of thecarboxylic acid silyl ester compound having an aliphatic unsaturatedgroup at a terminal and the alkoxysilane having a SiH group.

In each of the above production methods, a solvent may be added duringthe reaction. Although the solvent is not particularly limited, examplesinclude aromatic hydrocarbons such as toluene, xylene and benzene;aliphatic hydrocarbons such as pentane, hexane, heptane, nonane, octaneand decane; ethers such as dimethyl ether, methyl ethyl ether,tetrahydrofuran and dioxane; halogenated hydrocarbons such asperchloroethane, perchloroethylene, trichloroethane, chloroform andcarbon tetrachloride; amides such as dimethylformamide; and esters suchas ethyl acetate, methyl acetate and butyl acetate.

The organic silicon compound of the present invention has an alkoxysilylgroup and a carboxylic acid silyl ester group in one molecule, andregenerates a highly active carboxyl group by hydrolysis, thereby a roomtemperature-curable organopolysiloxane composition including the organicsilicon compound exhibits high stickiness/adhesion to a substrate.Therefore, the organic silicon compound of the present invention isuseful as a silane coupling agent, a silylating agent, an adhesion aid,or the like.

The amount of the carboxylic acid silyl ester group-containing silanecoupling agent as component (C) blended is 0.1 to 15 parts by weight,and preferably 0.3 to 10 parts by weight per 100 parts by weight ofcomponent (A). If the amount is less than 0.1 parts by weight,sufficient magnesium alloy adhesive properties cannot be obtained. Ifthe amount is more than 15 parts by weight, a cured product is hard andbrittle, which is further disadvantageous in cost.

[Component (D)]

In the organopolysiloxane composition of the present invention, a filler(D) can be blended. As the filler, a reinforcing or non-reinforcingfiller for imparting rubber properties to the composition can be used.Specific examples of such a filler include surface-treated oruntreated-, fumed silica, precipitated silica, wet silica, carbonpowder, talc and bentonite; surface-treated or untreated-, calciumcarbonate, zinc carbonate and magnesium carbonate; and surface-treatedor untreated-, calcium oxide, zinc oxide, magnesium oxide, aluminumoxide and aluminum hydroxide. These compounds may be used alone or incombination of two or more thereof.

The amount of the filler blended is preferably to provide 1 to 500 partsby weight, and more preferably 5 to 450 parts by weight per 100 parts byweight of component (A). If the amount is less than 1 part by weight,sufficient adhesive strength to a target magnesium alloy cannot beobtained in some cases due to insufficient rubber strength. If theamount exceeds 500 parts by weight, the viscosity of the material ishigh, and workability may be poor.

[Other Components]

For the organopolysiloxane composition of the present invention, inaddition to the above components, generally known additives, catalysts(particularly, condensation reaction catalysts) and the like may be usedas long as there is no adverse influence on curability at roomtemperature, self-adhesion to a magnesium alloy and the like. Examplesof the additive include polyether as a thixotropy improver, coloringagents such as pigment and dye, heat resistance improvers such as rediron and cerium oxide, cold resistance improvers, rust inhibitors,plasticizers, and oil resistance improvers such as potassiummethacrylate. Fungicides, antibacterial agents and the like are alsoadded as necessary. Examples of the catalyst (condensation reactioncatalyst) include organic metal compounds such as organic tin estercompound, organic tin chelate compound, alkoxytitanium compound andtitanium chelate compound, and silicon compound having guanidyl.

For the organopolysiloxane composition of the present invention, inaddition to the above components, generally known silane coupling agents(that is, a carbon functional silane compound having a functionalgroup-containing monovalent hydrocarbon group and at least twohydrolyzable groups in a molecule thereof) may also be used as long asthere is no adverse influence on curability at room temperature,self-adhesion to a magnesium alloy and the like. Examples thereofinclude epoxy group-containing alkoxysilanes such as 2-(3,4-epoxycyclohexyl) ethyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane,3-glycidoxypropyl methyldiethoxysilane and 3-glycidoxypropyltriethoxysilane; methacryloxy group-containing alkoxysilanes such as3-methacryloxypropyl trimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropyl methyldimethoxysilane and3-methacryloxypropyl methyldiethoxysilane; mercapto group-containingalkoxysilanes such as 3-mercaptopropyl trimethoxysilane and3-mercaptopropylmethyl dimethoxysilane; and ketimine group-containingalkoxysilanes such as N-(1,3-dimethylbutylidene)-3-aminopropyltrimethoxysilane and N-(1,3-dimethylbutylidene))-3-aminopropyltriethoxysilane.

[Preparation of Organopolysiloxane Composition]

A method for preparing the organopolysiloxane composition of the presentinvention is not particularly limited, and the organopolysiloxanecomposition can be obtained by mixing predetermined amounts of the abovecomponents according to a usual method.

In a case where the organopolysiloxane composition of the presentinvention is used for adhering to a magnesium alloy, theorganopolysiloxane composition is cured (cross-linked) by a condensationreaction at room temperature (23° C.±10° C.) by moisture in theatmosphere, and thereby a silicone rubber cured product exhibiting goodself-adhesion to the magnesium alloy even without a chemical conversiontreatment is obtained.

The organopolysiloxane composition is cured by being left at roomtemperature (23° C.±10° C.). As a method for molding theorganopolysiloxane composition, a condition for curing theorganopolysiloxane composition and the like, known methods andconditions can be adopted depending on the type of the composition.

EXAMPLES

Examples of synthesis, Synthesis Examples, Synthesis Reference Examples,Examples and Comparative Examples are given below for illustrating theinvention although the invention is not limited thereto. Note that inthe examples, parts and % indicate parts by weight and % by weight,respectively. Viscosity is a value measured with a rotational viscometerat 25° C. according to the method specified in JIS Z 8803.

Hereinafter, examples of synthesis of a terminal aliphatic unsaturatedgroup-containing carboxylic acid silyl ester compound used forsynthesizing the organic silicon compound of the present invention, andexamples of synthesis (Synthesis Examples) of the organic siliconcompound of the present invention are described. Note that a synthesizedcompounds were identified by ¹H-NMR, and the synthesis thereof wasconfirmed.

Example of Synthesis 1

In a separable flask having a capacity of 1,000 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 184 g (1mol) of 10-undecylenic acid, 119 g (1.1 mol) of trimethylchlorosilaneand 500 ml of toluene were put, and 111 g (1.1 mol) of triethylamine wasadded dropwise thereto over one hour in an ice bath. After completion ofthe dropwise addition, a reaction was caused at room temperature (23°C., the same applies hereinafter) for six hours. Thereafter, a generatedtriethylamine hydrochloride was removed by filtration. Furthermore,toluene and unreacted substances were removed (distilled off) at 150° C.at 300 Pa, thus obtaining 10-undecylenic acid trimethylsilyl ester as atarget product (collected amount: 226 g, yield: 72%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 5.46 (m, 3H), 2.48 (t, 2H), 1.88 (m, 2H), 1.08 (brs, 16H),        0.28 (s, 9H)

Example of Synthesis 2

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 50 g (0.27mol) of 10-undecylenic acid, 34 g (0.135 mol) of diphenyldichlorosilaneand 300 ml of toluene were put, and 30 g (0.3 mol) of triethylamine wasadded dropwise thereto over 30 minutes in an ice bath. After completionof the dropwise addition, a reaction was caused at room temperature forsix hours.

Thereafter, a generated triethylamine hydrochloride was removed byfiltration. Furthermore, toluene and unreacted substances were removed(distilled off) at 150° C. at 300 Pa, thus obtaining bis(10-undecylenicacid) diphenylsilyl ester as a target product (collected amount: 59 g,yield: 79%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 7.36 (m, 10H), 2.51 (t, 4H), 1.88 (m, 4H), 1.08 (brs, 32H),        0.28 (s, 18H)

Example of Synthesis 3

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 43 g (0.5mol) of 3-butenoic acid, 94 g (0.55 mol) of phenyldimethylchlorosilaneand 300 ml of toluene were put, and 55 g (0.55 mol) of triethylamine wasadded dropwise thereto over 30 minutes in an ice bath. After completionof the dropwise addition, a reaction was caused at room temperature forsix hours. Thereafter, a generated triethylamine hydrochloride wasremoved by filtration. Furthermore, toluene and unreacted substanceswere removed (distilled off) at 100° C. at 300 Pa, thus obtaining3-butenoic acid phenyldimethylsilyl ester as a target product (collectedamount: 78 g, yield: 71%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 7.32 (m, 5H), 5.72 (m, 3H), 2.48 (t, 2H), 0.31 (s, 6H)

Example of Synthesis 4

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 52 g (0.6mol) of 3-butenoic acid, 29 g (0.2 mol) of methyltrichlorosilane and 300ml of toluene were put, and 60 g (0.6 mol) of triethylamine was addeddropwise thereto over 30 minutes in an ice bath. After completion of thedropwise addition, a reaction was caused at room temperature for sixhours. Thereafter, a generated triethylamine hydrochloride was removedby filtration. Furthermore, toluene and unreacted substances wereremoved (distilled off) at 150° C. at 300 Pa, thus obtainingtris(3-butenoic acid) methylsilyl ester as a target product (collectedamount: 52 g, yield: 88%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 5.72 (m, 9H), 2.48 (t, 6H), 0.29 (s, 3H)

Example of Synthesis 5

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 69 g (0.8mol) of 3-butenoic acid, 33 g (0.2 mol) of tetrachlorosilane and 300 mlof toluene were put, and 80 g (0.8 mol) of triethylamine was addeddropwise thereto over 30 minutes in an ice bath. After completion of thedropwise addition, a reaction was caused at room temperature for sixhours. Thereafter, a generated triethylamine hydrochloride was removedby filtration. Furthermore, toluene and unreacted substances wereremoved (distilled off) at 150° C. at 300 Pa, thus obtainingtetra(3-butenoic acid) silyl ester as a target product (collectedamount: 61 g, yield: 83%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 5.72 (m, 12H), 2.48 (t, 8H)

Example of Synthesis 6

In a separable flask having a capacity of 1,000 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 86 g (1mol) of 3-butenoic acid, 119 g (1.1 mol) of trimethylchlorosilane and500 ml of toluene were put, and 111 g (1.1 mol) of triethylamine wasadded dropwise thereto over one hour in an ice bath. After completion ofthe dropwise addition, a reaction was caused at room temperature (23°C., the same applies hereinafter) for six hours. Thereafter, a generatedtriethylamine hydrochloride was removed by filtration. Furthermore,toluene and unreacted substances were removed (distilled off) at 120° C.at 2,000 Pa, thus obtaining 3-butenoic acid trimethyl silyl ester as atarget product (collected amount: 108 g, yield: 68%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 5.72 (m, 3H), 2.48 (t, 2H), 0.28 (s, 9H)

Synthesis Example 1

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 128 g (0.5mol) of the 10-undecylenic acid trimethylsilyl ester obtained in Exampleof synthesis 1 and 0.1 g of 0.5% Karstedt catalyst (platinum olefincompound complex) toluene solution were put, and the resulting mixturewas heated to 80° C. Next, 61 g (0.5 mol) of trimethoxysilane was addeddropwise thereto over two hours while the temperature range was adjustedto 80 to 100° C. After completion of the dropwise addition, a reactionwas caused at 80° C. for eight hours. Thereafter, unreacted substanceswere removed at 150° C. at 300 Pa, thus obtaining11-trimethoxysilylundecanoic acid trimethyl silyl ester as a targetproduct, represented by the following chemical formula (9) (collectedamount: 212 g, yield: 91%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.82 (s, 9H), 2.18 (t, 2H), 1.51 (m, 2H), 1.08 (brs, 14H),        0.78 (t, 2H), 0.28 (s, 9H)

Synthesis Example 2

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 25 g (0.045mol) of the bis(10-undecylenic acid) diphenylsilyl ester obtained inExample of synthesis 2 and 0.05 g of 0.5% Karstedt catalyst (platinumolefin compound complex) toluene solution were put, and the resultingmixture was heated to 80° C. Next, 15 g (0.12 mol) of trimethoxysilanewas added dropwise thereto over two hours while the temperature rangewas adjusted to 80 to 100° C. After completion of the dropwise addition,a reaction was caused at 80° C. for eight hours. Thereafter, unreactedsubstances were removed at 150° C. at 300 Pa, thus obtainingbis(11-trimethoxysilylundecanoic acid) diphenylsilyl ester as a targetproduct, represented by the following chemical formula (10) (collectedamount: 39 g, yield: 93%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 7.36 (m, 10H), 3.82 (s, 18H), 2.18 (t, 4H), 1.51 (m, 4H), 1.08        (brs, 28H), 0.78 (t, 4H), 0.28 (s, 18H)

Synthesis Example 3

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 66 g (0.3mol) of the 3-butenoic acid phenyldimethylsilyl ester obtained inExample of synthesis 3 and 0.05 g of 0.5% Karstedt catalyst (platinumolefin compound complex) toluene solution were put, and the resultingmixture was heated to 80° C. Next, 36 g (0.3 mol) of trimethoxysilanewas added dropwise thereto over two hours while the temperature rangewas adjusted to 80 to 100° C. After completion of the dropwise addition,a reaction was caused at 80° C. for eight hours. Thereafter, unreactedsubstances were removed at 100° C. at 300 Pa, thus obtaining4-trimethoxysilylbutanoic acid phenyldimethylsilyl ester as a targetproduct, represented by the following chemical formula (11) (collectedamount: 79 g, yield: 91%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 7.18 (m, 10H), 3.82 (s, 9H), 2.26 (t, 2H), 1.86 (m, 2H), 0.78        (t, 2H), 0.31 (s, 6H)

Synthesis Example 4

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 29 g (0.1mol) of the tris(3-butenoic acid) methylsilyl ester obtained in Exampleof synthesis 4 and 0.05 g of 0.5% Karstedt catalyst (platinum olefincompound complex) toluene solution were put, and the resulting mixturewas heated to 80° C. Next, 36 g (0.3 mol) of trimethoxysilane was addeddropwise thereto over two hours while the temperature range was adjustedto 80 to 100° C. After completion of the dropwise addition, a reactionwas caused at 80° C. for eight hours. Thereafter, unreacted substanceswere removed at 150° C. at 300 Pa, thus obtainingtris(4-trimethoxysilylbutenoic acid) methylsilyl ester as a targetproduct, represented by the following chemical formula (12) (collectedamount: 60 g, yield: 93%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.82 (s, 27H), 2.26 (t, 6H), 1.86 (m, 6H), 0.78 (t, 6H), 0.29        (s, 3H)

Synthesis Example 5

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 36 g (0.1mol) of the tetra(3-butenoic acid) silyl ester obtained in Example ofsynthesis 5 and 0.05 g of 0.5% Karstedt catalyst (platinum olefincompound complex) toluene solution were put, and the resulting mixturewas heated to 80° C. Next, 48 g (0.4 mol) of trimethoxysilane was addeddropwise thereto over two hours while the temperature range was adjustedto 80 to 100° C. After completion of the dropwise addition, a reactionwas caused at 80° C. for eight hours. Thereafter, unreacted substanceswere removed at 150° C. at 300 Pa, thus obtainingtetra(4-trimethoxysilylbutanoic acid) silyl ester as a target product,represented by the following chemical formula (13) (collected amount: 75g, yield: 90%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.82 (s, 36H), 2.26 (t, 8H), 1.86 (m, 8H), 0.78 (t, 8H)

Synthesis Example 6

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 128 g (0.5mol) of the 10-undecylenic acid trimethylsilyl ester obtained in Exampleof synthesis 1 and 0.1 g of 0.5% Karstedt catalyst (platinum olefincompound complex) toluene solution were put, and the resulting mixturewas heated to 80° C. Next, 53 g (0.5 mol) of methyldimethoxysilane wasadded dropwise thereto over two hours while the temperature range wasadjusted to 80 to 100° C. After completion of the dropwise addition, areaction was caused at 80° C. for eight hours. Thereafter, unreactedsubstances were removed at 150° C. at 300 Pa, thus obtaining11-methyldimethoxysilylundecanoic acid trimethyl silyl ester as a targetproduct, represented by the following chemical formula (14) (collectedamount: 196 g, yield: 94%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.82 (s, 6H), 2.18 (t, 2H), 1.51 (m, 2H), 1.08 (brs, 14H),        0.78 (t, 2H), 0.38 (s, 3H), 0.28 (s, 9H)

Synthesis Example 7

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 128 g (0.5mol) of the 10-undecylenic acid trimethylsilyl ester obtained in Exampleof synthesis 1 and 0.1 g of 0.5% Karstedt catalyst (platinum olefincompound complex) toluene solution were put, and the resulting mixturewas heated to 80° C. Next, 82 g (0.5 mol) of triethoxysilane was addeddropwise thereto over two hours while the temperature range was adjustedto 80 to 100° C. After completion of the dropwise addition, a reactionwas caused at 80° C. for eight hours. Thereafter, unreacted substanceswere removed at 150° C. at 300 Pa, thus obtaining11-triethoxysilylundecanoic acid trimethyl silyl ester as a targetproduct, represented by the following chemical formula (15) (collectedamount: 219 g, yield: 92%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.92 (q, 6H), 2.18 (t, 2H), 1.89 (t, 9H), 1.51 (m, 2H), 1.08        (brs, 14H), 0.78 (t, 2H), 0.28 (s, 9H)

Synthesis Reference Example 1

In a separable flask having a capacity of 500 ml and equipped with areflux tube, a dropping funnel, a stirrer and a thermometer, 79 g (0.5mol) of the 3-butenoic acid trimethylsilyl ester obtained in Example ofsynthesis 6 and 0.1 g of 0.5% Karstedt catalyst (platinum olefincompound complex) were put, and the resulting mixture was heated to 80°C. Next, 61 g (0.5 mol) of trimethoxysilane was added dropwise theretoover two hours while the temperature range was adjusted to 80 to 100° C.After completion of the dropwise addition, a reaction was caused at 80°C. for eight hours. Thereafter, unreacted substances were removed at130° C. at 300 Pa, thus obtaining 4-trimethoxysilylbutanoic acidtrimethyl silyl ester as a target product, represented by the followingchemical formula (16) (collected amount: 124 g, yield: 89%).

¹H-NMR (400 MHz, CDCl₃)

-   -   δ 3.82 (s, 9H), 2.26 (t, 2H), 1.86 (m, 2H), 0.78 (t, 2H), 0.28        (s, 9H)

Hereinafter, preparation examples (Examples) of an organopolysiloxanecomposition using the organic silicon compound of the present inventionare described.

Example 1

(Component A) 100 parts of dimethylpolysiloxane having a viscosity of20,000 mPas and being blocked at both terminal ends of the molecularchain with hydroxy groups each bonded to a silicon atom (silanolgroups), and (component D) 100 parts of heavy calcium carbonatesurface-treated with paraffin were uniformly mixed. To the resultingmixture, (component B) 9 parts of vinyltributanoxime silane and 0.6parts of dibutyltin dilaurate, and (component C) 1 part of the11-trimethoxysilylundecanoic acid trimethylsilyl ester obtained inSynthesis Example 1 were added and mixed under moisture shut-off untilthe mixture became uniform, thus preparing Composition 1.

Example 2

Composition 2 was prepared in the same manner as Example 1 except that(component C) 1 part of the bis(l 1-trimethoxysilylundecanoic acid)diphenylsilyl ester obtained in Synthesis Example 2 was used instead of(component C) 1 part of 11-trimethoxysilylundecanoic acid trimethylsilyl ester.

Example 3

Composition 3 was prepared in the same manner as Example 1 except that(component C) 1 part of the 4-trimethoxysilylbutanoic acidphenyldimethylsilyl ester obtained in Synthesis Example 3 was usedinstead of (component C) 1 part of 11-trimethoxysilylundecanoic acidtrimethyl silyl ester.

Example 4

Composition 4 was prepared in the same manner as Example 1 except that(component C) 1 part of the tris(4-trimethoxysilylbutenoic acid)methylsilyl ester obtained in Synthesis Example 4 was used instead of(component C) 1 part of 11-trimethoxysilylundecanoic acid trimethylsilyl ester.

Example 5

Composition 5 was prepared in the same manner as Example 1 except that(component C) 1 part of the tetra(4-trimethoxysilylbutanoic acid) silylester obtained in Synthesis Example 5 was used instead of (component C)1 part of 11-trimethoxysilylundecanoic acid trimethyl silyl ester.

Example 6

Composition 6 was prepared in the same manner as Example 1 except that(component C) 1 part of the 11-methyldimethoxysilylundecanoic acidtrimethyl silyl ester obtained in Synthesis Example 6 was used insteadof (component C) 1 part of 11-trimethoxysilylundecanoic acid trimethylsilyl ester.

Example 7

Composition 7 was prepared in the same manner as Example 1 except that(component C) 1 part of the 11-triethoxysilylundecanoic acid trimethylsilyl ester obtained in Synthesis Example 7 was used instead of(component C) 1 part of 11-trimethoxysilylundecanoic acid trimethylsilyl ester.

Comparative Example 1

Composition 8 was prepared in the same manner as Example 1 except that 1part of N-2-(aminoethyl)-3-aminopropyltrimethoxysilane was used insteadof (component C) 11-trimethoxysilylundecanoic acid trimethyl silylester.

Comparative Example 2

Composition 9 was prepared in the same manner as Example 1 except that 1part of 3-aminopropyltrimethoxysilane was used instead of (component C)11-trimethoxysilylundecanoic acid trimethyl silyl ester.

Next, each of the compositions immediately after preparation in theabove Examples 1 to 7 and Comparative Examples 1 and 2 was sandwichedbetween magnesium alloy plates (AZ-91D) having a width of 25 mm and alength of 50 mm, and a shear bond test specimen having a bond area of2.5 mm² and a bond thickness of 1 mm was prepared. The shear bond testspecimen was cured at 23° C. at 50% RH for seven days. Thereafter, ashear bond force and a cohesive failure ratio were measured according tothe method specified in JIS K 6249, and comparison of the cohesivefailure ratio was performed. The results are shown in Table 1.

TABLE 1 Example Comparative Example Unit 1 2 3 4 5 6 7 1 2 AZ-91D MPa1.1 1.1 1.2 1.0 1.1 1.0 1.0 0.4 0.3 shear bond force Cohesive failureratio % 100 100 100 100 100 100 100 0 0

It has been found that the organic silicon compound of the presentinvention is blended in a room temperature-curable organopolysiloxanecomposition (silicone rubber composition), thereby excellent adhesion tomagnesium alloy of an adherend having very poor adhesiveness is impartedto the silicon rubber cured product obtained by curing the composition.Meanwhile, adhering to a magnesium alloy could not be achieved with anamine-based bonding aid that has been generally used. Therefore, byadding to a room temperature-curable organopolysiloxane composition, theorganic silicon compound of the present invention can impart betteradhesive properties than a conventional adhesion aid.

Hereinafter, Preparation Examples (Examples) of the organopolysiloxanecomposition of the present invention are described.

Example 8

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane and 0.1 parts by weight of dioctyltindilaurate, and (component C) 1 part by weight of the4-trimethoxysilylbutanoic acid trimethylsilyl ester obtained inSynthesis Reference Example 1 were added thereto and thoroughly mixedunder reduced pressure to obtain Composition 10.

Example 9

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane and 0.1 parts by weight of dioctyltindilaurate, and (component C) 1 part by weight of the11-trimethoxysilylundecanoic acid trimethyl silyl ester obtained inSynthesis Example 1 were added thereto and thoroughly mixed underreduced pressure to obtain Composition 11.

Example 10

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane and 0.1 parts by weight of dioctyltindilaurate, and (component C) 1 part by weight of thebis(11-trimethoxysilylundecanoic acid) diphenylsilyl ester obtained inSynthesis Example 2 were added thereto and thoroughly mixed underreduced pressure to obtain Composition 12.

Example 11

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane and 0.1 parts by weight of dioctyltindilaurate, and (component C) 1 part by weight of the11-trimethoxysilylundecanoic acid trimethylsilyl ester obtained inSynthesis Example 1 and 1 part by weight ofN-(1,3-dimethylbutylidene)-3-aminopropyl trimethoxysilane (product name;KBM-9103P, manufactured by Shin-Etsu Chemical Co., Ltd.) were addedthereto and thoroughly mixed under reduced pressure to obtainComposition 13.

Comparative Example 3

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane, 0.1 parts by weight of dioctyltin dilaurate,and 1 part by weight of 3-aminopropyl trimethoxysilane were addedthereto and thoroughly mixed under reduced pressure to obtainComposition 14.

Comparative Example 4

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPas and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane, 0.1 parts by weight of dioctyltin dilaurate,and 1 part by weight of allylic succinic anhydride silane (product name;X-31-967C, manufactured by Shin-Etsu Chemical Co., Ltd.) were addedthereto and thoroughly mixed under reduced pressure to obtainComposition 15.

Comparative Example 5

To (component A) 100 parts by weight of dimethylpolysiloxane having aviscosity of 5,000 mPa·s and being blocked at both terminal ends of themolecular chain with hydroxy groups each bonded to a silicon atom(silanol groups), (component D) 100 parts by weight of heavy calciumcarbonate surface-treated with a fatty acid (product name; MC coat P-20,manufactured by Maruo Calcium Co., Ltd.) was added and mixed with amixer. Thereafter, (component B) 10 parts by weight ofvinyltributanoxime silane, 0.1 parts by weight of dioctyltin dilaurate,and 1 part by weight of the 3-butenoic acid trimethylsilyl esterobtained in Synthesis Example 6 were added thereto and thoroughly mixedunder reduced pressure to obtain Composition 16.

Each of the compositions immediately after preparation in Examples 8 to11 and Comparative Examples 3 to 5 was poured into a 2 mm mold and curedat 23° C. at 50% RH for seven days to obtain a 2 mm thick rubber sheet.Rubber properties (hardness, elongation at break, and tensile strength)were measured with the 2 mm thick sheet according to JIS K6249.

Each of the compositions immediately after preparation in Examples 8 to11 and Comparative Examples 3 to 5 was sandwiched between magnesiumalloy plates (AZ-91D) having a width of 25 mm and a length of 50 mm, anda shear bond test specimen having a bond area of 2.5 mm² and a bondthickness of 1 mm was prepared. The shear bond test specimen was curedat 23° C. at 50% RH for seven days. Thereafter, a shear bond force and acohesive failure ratio were measured according to the method specifiedin JIS K6249, and comparison of the cohesive failure ratio wasperformed.

In order to confirm chemical resistance (CVTF resistance), the obtainedcured silicone rubber sheet and shear bond test specimen were immersedin CVTF oil [trade name: ULTRA Honda Multi Mafic Fluid] and deterioratedat 150° C. for seven days. Thereafter, the same test to that as in theinitial stage of production was performed, thus conducting chemicalresistance confirmation test.

Results thereof are shown in Table 2.

TABLE 2 Example Comparative Example Unit 8 9 10 11 3 4 5 Initial stageHardness (Type: A) — 59 58 58 60 62 59 56 of production Elongation atbreak % 260 270 260 320 240 280 360 Tensile strength MPa 1.7 1.7 1.6 1.81.9 1.7 1.9 AZ-91D MPa 1.5 1.6 1.4 1.5 0.6 1.4 0.3 shear bond forceCohesive failure ratio % 100 100 100 100 0 100 0 Chemical Hardness(Type: A) — 13 15 16 14 6 13 20 resistance Elongation at break % 250 310240 280 410 310 280 Tensile strength MPa 0.9 1.1 1.0 1.0 0.5 0.9 1.4AZ-91D MPa 0.7 0.8 0.7 0.9 0.1 0.2 0.1 shear bond force Cohesive failureratio % 70 100 100 100 0 0 0

It is found that the compositions of Examples 8 to 11 each containingthe carboxylic acid silyl ester group-containing silane coupling agentof the present invention have high adhesion to AZ-91D both in theinitial stage of production and after the chemical resistance test.Meanwhile, the composition of Comparative Example 3 using a generallyused amine-based silane coupling agent did not exhibit adhesion(cohesive failure) to AZ-91D at all and deteriorated chemicalresistance. The composition of Comparative Example 4 using an allylicsuccinic anhydride silane coupling agent had good adhesive properties inthe initial stage of production, but was peeled off from AZ-91D afterthe chemical resistance test. The composition of Comparative Example 5using a carboxylic acid silyl ester compound alone free of hydrolyzablealkoxysilane in a molecule thereof did not exhibit adhesive properties.From the above results, it is indicated that the composition of thepresent invention has high adhesion to a magnesium alloy both in theinitial stage of production and after the chemical resistance test.

The invention claimed is:
 1. An organic silicon compound having thegeneral formula (3A):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b′ is an integer of 0 to
 2. 2. An organic silicon compound havingthe general formula (3B):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a is an integer of 0 to 2and b″ is an integer of 1 to 3, with the proviso that at least one of R³is an aryl group.
 3. An organic silicon compound having the generalformula (3C):

wherein R¹, R², and R³ are each independently a C₁-C₁₀ monovalenthydrocarbon group, k is an integer of 3 to 14, a′ is 1 or 2 and b is aninteger of 0 to 3, with the proviso that k is an integer of 6 to 14 in acase where R³ is an aliphatic saturated monovalent hydrocarbon group andb=3.
 4. A method for producing the organic silicon compound (3A) ofclaim 1, the method comprising reacting a carboxylic acid silyl estercompound having an aliphatic unsaturated group at a terminal,represented by the general formula (5A):

wherein R³, b′ and k are as defined for general formula (3A), with analkoxysilane having the general formula (8):

wherein R¹, R² and a are as defined for general formula (3A).
 5. Themethod for producing the organic silicon compound according to claim 4,wherein the carboxylic acid silyl ester compound having an aliphaticunsaturated group at a terminal, represented by the general formula (5A)is obtained by a reaction between a carboxylic acid having an aliphaticunsaturated group at a terminal, represented by the general formula (6):

wherein k is as defined for general formula (3A), and a halosilanehaving the general formula (7A):

wherein R³ and b′ are as defined for general formula (3A), and X is ahalogen atom.
 6. A method for producing the organic silicon compound(3B) of claim 2, the method comprising reacting a carboxylic acid silylester compound having an aliphatic unsaturated group at a terminal,represented by the general formula (5B):

wherein R³, b″ and k are as defined for general formula (3B) with theproviso that at least one of R³ is an aryl group, with an alkoxysilanehaving the general formula (8):

wherein R¹, R² and a are as defined for general formula (3B).
 7. Themethod for producing the organic silicon compound according to claim 6,wherein the carboxylic acid silyl ester compound having an aliphaticunsaturated group at a terminal, represented by the general formula (5B)is obtained by a reaction between a carboxylic acid having an aliphaticunsaturated group at a terminal, represented by the general formula (6):

wherein k is as defined for general formula (3B), and a halosilanehaving the general formula (7B):

wherein R³ and b″ are as defined for general formula (3B), and X is ahalogen atom.
 8. A method for producing the organic silicon compound(3C) of claim 3, the method comprising reacting a carboxylic acid silylester compound having an aliphatic unsaturated group at a terminal,represented by the general formula (5):

wherein R³, b and k are as defined for general formula (3C), with theproviso that k is an integer of 6 to 14 in a case where R³ is analiphatic saturated monovalent hydrocarbon group and b=3, with analkoxysilane having the general formula (8C):

wherein R¹, R² and a′ are as defined for general formula (3C).
 9. Themethod for producing the organic silicon compound according to claim 8,wherein the carboxylic acid silyl ester compound having an aliphaticunsaturated group at a terminal, represented by the general formula (5)is obtained by a reaction between a carboxylic acid having an aliphaticunsaturated group at a terminal, represented by the general formula (6):

wherein k is as defined for general formula (3C), and a halosilanehaving the general formula (7):

wherein R³ and b are as defined for general formula (3C), and X is ahalogen atom.